In view of energy saving, a low temperature fixing technique to minimize electric power consumption has recently been developed in the electrophotographic industry.
There was a problem in storage stability such that an electrostatic charge image developing toner (hereinafter, referred to simply as toner) capable of being fixed at low temperature resulted in toner off-set during image formation, and the toner coagulated during storage in a toner bottle or a cartridge.
In order to achieve a good balance between no occurrence of off-setting and storage stability, methods of preparing a toner including toner particles each having a core/shell structure have recently been intensively studied.
It is known as a process of preparing toner including toner particles each having a core/shell structure that the core is formed by fusing and coagulation of resin particles prepared via polymerization of a polymerizable monomer in a solution, and a shell layer is further formed on the core surface by adding a resin particle solution.
However, in the case of a process of manufacturing toner including toner particles each having a core/shell structure by adding resin particles to prepare the shell after formation of the foregoing core portion, a coagulation/fusing process was required to be conducted twice for forming both the core and the shell. Consequently, as the case stands now, a complicated manufacturing process with a long manufacturing duration is required to be carried out.    (Patent Document 1) Japanese patent O.P.I. Publication No. 2004-109939    (Patent Document 2) Japanese patent O.P.I. Publication No. 2002-116574